Stock-Based Compensation Expense (Detail) (Stock Based Compensation Expense, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated share based compensation expense	$ 1,202	$ 1,144
Cost of Goods Sold
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated share based compensation expense	243	188
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated share based compensation expense	418	469
Selling and Marketing Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated share based compensation expense	238	209
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated share based compensation expense	$ 303	$ 278